Note: The V9938 / V9958 VDP Card is supplied in Kitset form only (assembly required). The base price is for the double-sided silkscreened V9938 / V9958 VDP Card PCB ONLY. The optional packs provide most components. 4464 DRAM & IC Sockets are also required to make a complete V9938 / V9958 VDP Card Kitset. See BOM below (and photo).

What is Minimalist Europe Card Bus

Europe Card Bus (ECB) is a Retro CPU Bus standard from the late 1970’s / early 1980’s.

The “Minimalist Europe Card Bus” (as I’ve called it), is a Retro 8-bit CPU Bus and PCB design standard that I decided to define & document. The purpose of which is to provide a modular platform for me to re-experience the fun of experimenting with the different 8-bit CPU’s, and the various Video and Peripheral devices, that I grew up with in the late 1970’s and early 1980’s.

My goal is that of a robust and modular Design Platform which allows me to create interchangeable PCB cards, based on time proven reliable bus connectors and modern low-cost prototype PCB manufacturing.

i.e. A robust, flexible, and low cost way for me to re-create some of the early microprocessor circuits, that I’d originally built using Wire-Wrap methods, back in the day.

As evident from the name, the Bus itself is based on a Minimalist implementation of the original Europe Card Bus (ECB) standard.

Standardised Mechanical Specification for a Minimalist ECB “MECB” Board

MECB Standardised Board Design Parameters:

• Satisfy the 100mm square maximum board size, for low-cost prototype PCB manufacturing.
• Utilise the lower cost 64-pin (Row A&C) DIN 41612 type C connectors, for cost saving.
• Ensure the DIN 41612 connector(s) can be easily centred across the board width, grid aligned.
• Provide two standardised corner holes, on the edge opposing the right-angle DIN connector, to allow for attachment of card handles (to ease board insertion & extraction), or for board mounting – refer next point.
• Provide an additional two standardised corner mounting holes on the edge with the right-angle DIN connector, to provide a full set of four corner holes (to allow for stand-alone board mounting).
• Standardise PCB corner rounding, for sharp corner removal consistency across all boards & visual tidiness.

MECB Standardised Board Design Notes:

• PCB layout is designed utilising 0.127mm (5.0 mils) grid setting.
• Board size is 99.822mm, which represents the greatest even multiple of 0.127mm (i.e. multiple of 0.254mm – 10.0 mils), that will fit within the desired maximum 100mm board dimension.
• Standard M3 sized mounting holes were chosen. An additional two mid-edge located mounting holes are specified for Backplane boards only (to provide additional mechanical support).
• For reference, DIN 41612 connectors can utilise standard M2.5 mounting bolts (8mm length for the straight connectors, 10mm length for right angle connectors).
• Implemented as a KiCAD Template, to assist enthusiasts by simplifying the creation of each new MECB board design.

Please refer to the attached photo outlining all dimensions for the MECB Standardised Board Mechanical Specifications.

V9938 or V9958 VDP Video Display Card

Why?

Ever since creating my existing TMS9918/992x VDP Card (listed separately in my Tindie Store), I've thought that I'd also like to play with the TMS's more capable successors, the V9938 and V9958 VDP's. Also known as the MSX-Video Display Processors.

Where the TMS VDP chip was chosen for the original MSX standard home computers. The success of the MSX standard drove the evolution of the VDP to it's much more capable successor, the V9938, which became the display processor of the later MSX2 standard.

One of the great things about these MSX2 VDP chips, is their backward compatibility.

So, you can use a V9938 based display card in place of a TMS display card, running the software that was written for the TMS9918 family.

However, the V9938 also greatly expands on the TMS families capabilities, offering more display modes and twice the resolution.

In addition, the V9938 provides a direct linear RGBS output, meaning that output drivers (like the TMS-RGB module that I used with the TMS9918/992x VDP Card), are no longer required in order to obtain a sharp RGBS output. Furthermore, the colors definitely have more pop, when compared to the earlier TMS family display output.

So, in summary, you can use the V9938 in place of a TMS VDP, and benefit from both better color and sharp RGBS output with no need for a TMS-RGB module. In addition, you have more display modes and twice the resolution to play with.

The V9938 was then later further enhanced as the V9958, which added a few more capabilities and featured in MSX2+ computers.

This VDP Card has all the makings for being my new favourite Video Display Card!

What You Get

To satisfy different people's needs, I've split the V9938 / V9958 VDP Card Kitset into optional add-on packs.

Firstly, note that the base price is for the double-sided silkscreened V9938 / V9958 VDP Card PCB Only.

Then, you can add the optional Packs that might be helpful to you. Then, to complete the Kitset, you'll need to source the 4464 DRAM chips and common IC Sockets. 4464 DRAM are commonly available from eBay etc.

Optional Hardware Pack includes:

• 1x Right Angle Male DIN41612 364 Keyed Bus Connector
• 2x M2.5 Stainless Steel Bolt 10mm (2 required for Right Angle Connector)
• 2x M2.5 Stainless Steel Hexagonal Nut (for above Bolts)
• 4x 12mm Nylon PCB Spacer
• 8x 6mm Nylon Bolt (for Spacer mounting)
• 1x 3.5mm Phone Connector Audio Jack PCB Mount (J2)
• 1x 9 pin Circular Mini-DIN Connector PCB Mount (J3)
• 1x 3 pin PCB Header (J4)
• 2x 2 pin PCB Header (JP1,JP2)
• 2x 2 pin Jumper Cap

Optional Discrete Components Pack includes:

• 1x 21.477MHz Crystal HC49-U (Y1)
• 4x 2N3904 NPN BJT TO-92 (Q1,Q2,Q3,Q4)
• 1x B-01-A Ferrite Bead Axial (FB1)
• 2x 22pf Capacitor 5mm (C1, C2)
• 6x 0.1µf Capacitor 5mm (C3,C4,C5,C6,C7,C8)
• 1x 47µf Capacitor 2.5mm (C9)
• 2x 10K Axial Resistor 7.62mm (R1,R2)
• 4x 1K Axial Resistor 7.62mm (R3,R4,R5,R6)
• 4x 220R Axial Resistor 7.62mm (R7,R8,R9,R10)
• 1x 75R Axial Resistor 7.62mm (R11)
• 3x 22R Axial Resistor 7.62mm (R12,R13,R14)

Optional Programmed ATF16V8 PLD Pack includes:

• An ATF16V8 PLD Chip (U1) Tested and Programmed as per the linked Video ($80-$87 I/O Address).

Optional Tested V9938 or V9959 + IC Socket Pack includes:

Either:

• Verified Operational V9938 MSX-Video VDP DIP64 Chip (U2)
• DIP64 IC Socket 1.77mm pitch (for U2)

OR:

• Verified Operational V9958 MSX-Video VDP DIP64 Chip (U2)
• DIP64 IC Socket 1.77mm pitch (for U2)

V9938 / V9958 VDP Card BOM

The following is a full Bill Of Materials (BOM) to allow fully assembling your V9938 / V9958 VDP Card.

Note that the PCB is supplied, and most components are available in the four optional packs. The 4464 DRAM chips and common IC Sockets will need to be sourced by yourself. 4464 DRAM chips are commonly available from eBay etc.

Also, some components are of course optional. For example the regular IC Sockets, although I do highly recommend IC Sockets are used for all ICs.

I have also included an indication of where I sourced my parts from, if this is of assistance.

The Video linked below, provides a full presentation of the V9938 or V9958 VDP Card, as well as demonstrating the steps I took for assembly, and a walkthrough of the 6809 code I used for testing.

Via the Documentation link (below) you'll also find follow-up videos, and other videos presenting different components of the MECB retro 8-bit computing project.

Your V9938 or V9958 VDP Card Kitset order is shipped in a robust cardboard carton with packing, for safe delivery via New Zealand International Air Parcel (see example shipping photo).

Note: Please visit the Documentation link (below) for more information on MECB, and for details of the various MECB Cards that have been design so far.